The photocatalytic activity of wide bandgap semiconductors has been the subject of numerous studies due to their ability to simultaneously harvest solar energy and drive chemical reactions via photoexcited charge carriers and activated electronic states.1-3 Among these materials, titanium dioxide (TiO2), also known as titania, is particularly noteworthy because of its robust performance, nontoxicity, and chemical stability. Numerous photocatalytic applications for TiO2 have been proposed including liquid and gas phase organic contaminant degradation, water photolysis, and carbon dioxide (CO2) reduction.1-4 A popular pathway for enhancing photocatalytic activity is to explore different TiO2 formulations including mixtures of its two polymorphs, anatase and rutile. While anatase typically exhibits higher photocatalytic activity than rutile, precise mixtures of both phases display even better performance. For example, the most widely studied TiO2 formulation is Degussa P25 TiO2 (P25), which at 80% anatase and 20% rutile, produces novel electronic states at anatase-rutile junctions that result in enhanced charge carrier separation and reduced electron-hole recombination.2,5 
More recently, further enhancements to TiO2 photocatalytic activity have been demonstrated by incorporating carbon nanomaterials to form carbon-TiO2 nanocomposite photocatalysts. In particular, carbon nanotubes (CNTs) and graphene, which are cylindrical and planar forms of sp2 hybridized carbon, respectively, have been shown to enhance catalysis6,7 due to their large specific surface areas, extraordinary electronic mobility,8 and molecular stability.9 In particular, previous studies have demonstrated the enhanced photo-oxidative degradation of organic contaminants for both CNT-based and graphene-based TiO2 nanocomposites.6,7,10-12 In these cases, the improved reactivity was attributed to the extended optical absorption, resulting from surface impurity doping, and increased lifetimes of the TiO2 confined holes, due to the injection of photoexcited electrons into the carbon nanomaterial.6,10 However, since these photo-oxidative reactions occur primarily on the unmodified TiO2 surface, few discernable differences have been reported between nanocomposites based on different carbon polymorphs.11 
Recent advances in the solution-phase isolation of graphene from graphite13-18 have motivated its study and use in photocatalytic nanocomposites. These solution-phase methods can be classified in two qualitatively different categories. The first and most commonly used strategy involves the covalent modification of graphite via acidic treatments to form an intermediary product that is frequently referred to as graphene oxide (GO). The GO nanoplatelets are then reduced through additional thermal,19 optical,20,21 or chemical means15 that partially restore sp2 hybridization to yield reduced graphene oxide (RGO).16 The second pathway employs ultrasonic energy to directly exfoliate graphite in suitable solvents.17,18 Sedimentation steps are then utilized to isolate the thinnest platelets to yield solvent-exfoliated graphene (SEG) dispersions. Recent studies have uncovered significant structural and chemical defects that distinguish RGO and SEG from both the ideal graphene crystal and one another.18,22 Since these defects produce unique electronic23,24 and optical25 states, they are likely to influence and perhaps even enhance photocatalysis.26 
Further, recent developments in low-dimensional nanomaterial synthesis have enabled their incorporation and study in a broad range of technologies. In particular, single walled carbon nanotubes (SWCNTs) and graphene, one and two-dimensional forms of sp2 hybridized carbon, respectively, have been utilized in high-performance transistors with high on/off ratios and frequencies exceeding 100 GHz.34-36 Concurrently, materials chemists have developed techniques to manipulate the geometry and direct the assembly of low-dimensional inorganic nanocrystals.37-40 By controlling their surface energies, highly monodisperse nanocrystal populations can be produced with tailored optoelectronic37,41, and catalytic42 properties. While isolated nanomaterials in pristine conditions are suitable for fundamental studies, most applications require integration into composite structures and operation in ambient environments. Consequently, precise understanding and control of nanomaterial surfaces and interfaces are needed to realize their full potential in practical settings.43 For example, the transfer of graphene onto flat boron nitride substrates results in increased electron mobility,44 and the preferential growth of (001) surfaces enhances the photoactivity of titania nanosheets (TiNS).42,45,46 
Due to its ability to degrade organic pollutants and produce chemical fuels using radiant energy, photo catalysis represents an attractive opportunity to utilize the unique optoelectronic properties and large specific surface areas of low-dimensional nanomaterials.47-63 In particular, nanocarbon-titania (TiO2) composites have been the subject of extensive investigation due to their ability to increase reactive charge carrier lifetimes and extend optical absorption into the visible spectrum.53-58 Various composites have been produced from combinations of TiO2 with SWCNT, solvent exfoliated graphene (SEG), or reduced graphene oxide (RGO).50-55,60,64-66 Recent work has shown that titania composite photocatalysts derived from SEG, which have low carbon defect densities, outperform those derived from RGO, which have high carbon defect densities, due to stronger optoelectronic coupling.53 However, the interfacial charge transfer interactions between TiO2 and different carbon nanomaterials are not completely understood.53,57,59,60 The high photoactivity and 2D geometry of recently discovered titania nanosheets (TiNS) provides a unique opportunity to engineer higher catalytic efficiencies and understand nanomaterial coupling in carbon-TiO2 nanocomposites.
Therefore, a heretofore unaddressed need exists in the art to address the aforementioned deficiencies and inadequacies.